A site template is a package that contains a set of differences from a base site definition. Site templates let you use a browser to easily create a template site from an existing SharePoint site. The site, including pages, lists, libraries, and contents, is archived into a single .stp file.
Site Template Pros. Site templates enable administrators to create predefined sites to simplify site provisioning from a user perspective. Sites that are created with them are consistent, which improves usability and maintenance. The pages are stored in just one location—the content database.
Site Template Cons. Because the pages are stored in the content database, performance degradation could occur. Once you create and save a template, you can't update it, which might lead to future product compatibility issues.
The another option is that, You should use Site Definition
Site Definition Pros. Administrators must programmatically create site definitions, giving them more control over site creation. Sites can be provisioned easilyusers don’t have to customize them. Site definitions provide greater control over a site's look and feel. Because sites are more consistent, there are fewer user support calls for help.
Site Definition Cons. Creating site definitions requires programming skills (i.e., Visual Studio). Site definitions are costly to maintain. The definition files are stored on each WFE server; therefore, updates must follow change control management processes when multiple WFE servers are involved.